Smut (fungus) in the context of "Basidiomycete"

The Basidiomycota (/bəˌsɪdi.oʊmaɪˈkoʊtə/) are one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. This division includes: agarics, puffballs, stinkhorns, bracket fungi, other polypores, jelly fungi, boletes, chanterelles, earth stars, smuts, bunts, rusts, mirror yeasts, and Cryptococcus, the human pathogenic yeast.

Basidiomycota are filamentous fungi composed of hyphae (except for basidiomycota-yeast) and reproduce sexually via the formation of specialized club-shaped end cells called basidia that normally bear external meiospores (usually four). These specialized spores are called basidiospores. However, some Basidiomycota are obligate asexual reproducers. Basidiomycota that reproduce asexually (discussed below) can typically be recognized as members of this division by gross similarity to others, by the formation of a distinctive anatomical feature (the clamp connection), cell wall components, and definitively by phylogenetic molecular analysis of DNA sequence data.

The Agaricomycetes are a class of fungi in the division Basidiomycota. The taxon is roughly identical to that defined for the Homobasidiomycetes (alternatively called holobasidiomycetes) by Hibbett & Thorn, with the inclusion of Auriculariales and Sebacinales. It includes not only mushroom-forming fungi, but also most species placed in the deprecated taxa Gasteromycetes and Homobasidiomycetes. Within the subdivision Agaricomycotina, which already excludes the smut and rust fungi, the Agaricomycetes can be further defined by the exclusion of the classes Tremellomycetes and Dacrymycetes, which are generally considered to be jelly fungi. However, a few former "jelly fungi", such as Auricularia, are classified in the Agaricomycetes. According to a 2008 estimate, Agaricomycetes include 17 orders, 100 families, 1147 genera, and about 21000 species. Modern molecular phylogenetic analyses have been since used to help define several new orders in the Agaricomycetes: Amylocorticiales, Jaapiales, Stereopsidales, and Lepidostromatales.

In mycology, a stipe (/staɪp/) is the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal tissue. In many instances, however, the fertile hymenium extends down the stipe some distance. Fungi that have stipes are said to be stipitate.

The evolutionary benefit of a stipe is generally considered to be in mediating spore dispersal. An elevated mushroom will more easily release its spores into wind currents or onto passing animals. Nevertheless, many mushrooms do not have stipes, including cup fungi, puffballs, earthstars, some polypores, jelly fungi, ergots, and smuts.

A basidiospore is a reproductive spore produced by basidiomycete fungi, a grouping that includes mushrooms, shelf fungi, rusts, and smuts. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. Typically, four basidiospores develop on appendages from each basidium, of which two are of one strain and the other two of its opposite strain. In gills under a cap of one common species, there exist millions of basidia.

Some gilled mushrooms in the order Agaricales have the ability to release billions of spores. The puffball fungus Calvatia gigantea has been calculated to produce about five trillion basidiospores. Most basidiospores are forcibly discharged, and are thus considered ballistospores. These spores serve as the main air dispersal units for the fungi. The spores are released during periods of high humidity and generally have a night-time or pre-dawn peak concentration in the atmosphere.